Fix Info.plist system properties for symlinked container. (#859)

- Regular `Bundle.main.infoDictionary` doesn't work in this case.
- Load bundle using location presuming binary is under `Contents/MacOS`.

Sources/ContainerVersion/Bundle+AppBundle.swift

@@ -0,0 +1,30 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2025 Apple Inc. and the container project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+import Foundation
+
+/// Retrieve the application bundle for a path that refers to a macOS executable.
+extension Bundle {
+    public static func appBundle(executableURL: URL) -> Bundle? {
+        let macOSURL = executableURL.deletingLastPathComponent()
+        let contentsURL = macOSURL.deletingLastPathComponent()
+        let bundleURL = contentsURL.deletingLastPathComponent()
+        if bundleURL.pathExtension == "app" {
+            return Bundle(url: bundleURL)
+        }
+        return nil
+    }
+}

Sources/ContainerVersion/ReleaseVersion.swift

@@ -30,7 +30,9 @@ public struct ReleaseVersion {
     }
 
     public static func version() -> String {
-        let bundleVersion = (Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String)
+        let executableURL = URL(fileURLWithPath: CommandLine.arguments[0]).resolvingSymlinksInPath()
+        let appBundle = Bundle.appBundle(executableURL: executableURL)
+        let bundleVersion = appBundle?.infoDictionary?["CFBundleShortVersionString"] as? String
         return bundleVersion ?? get_release_version().map { String(cString: $0) } ?? "0.0.0"
     }